UNIO. 517 
é 
46. Unio opacatus. 
Unio opacatus, Cross & Fisch. Journ. de Conch. xli. p. 295 (1898) *; Miss. Scient. Mex., Moll. ii. 
p. 592, t. 66. figg. 1, 1 a’. 
Hab. Mexico (Sallé } 2). 
Perhaps only a somewhat shorter variety of U. mevicanus. 
r 47. Unio mexicanus. 
Unio mexicanus, Philippi, Zeitschr. f. Malak. iv. p- 75 (1847)*; Abbild. neuer Conch. iii. p. 36, 
t. 6. fig. 3°; Kiister, in Martini & Chemnitz, Syst. Conch.-Cat. ed. 2, Unio, p. 285, t. 95. 
fig. 7 (copy from Philippi) *. 
Elliptic, angularly produced behind, smooth, brown; inside purple. 
Hab. Mexico (Liebmann * 1°), 
It is strange that this species has not been met with by later travellers. 
« 48. Unio sallei. 
Unio sallei, Crosse & Fisch. Journ. de Conch. xli. p. 179 (1898)*; Miss. Scient. Mex., Moll. ii. 
p- 619, t. 68. figg. 3, 3a’. 
Differs from U. mewicanus, Phil., in having the part before the summits shorter and the hinder extremity more 
rounded. 
Hab. Mexico (Sallé 1 2). 
Type of the section Pachynaias of Crosse and Fischer. 
Var. grossus,n. (Tab. XXXIV. figg. 2, 2a, 6.) 
Shorter, and therefore comparatively higher, than the typical form of JU. sallei, very thick, fore side regularly 
rounded, dorsal margin descending from the summits in a nearly straight, slightly convex line to the 
hinder extremity ; a very obtuse ridge descends from the summits to the hinder end of the ventral margin, 
and forms here a slight prominence ; ventral margin much ascending before, slightly convex at the middle, 
subsinuated behind. Inside white. Cardinal teeth rather strong. : 
Long. 62; alt. vert. 44, ale 38, diam. 30 millim. Vertices in 3 long. 
Hab. N. Guaremata : Rio Salinas (Séo/0). 
* 49. Unio medellinus. (Tab. XXXIX. figg. 7, 7a, 6.) 
? Unio purpuriatus, Say, New Harmony Disseminator of Useful Knowledge, 1831, p. 6’; Conrad, 
Proc. Acad. Phil. vi. p. 255 * (nee U. purpuratus, Lam., 1819). 
* Unio medellinus, Lea, Trans. Am. Phil. Soc. vi. p. 39, t. 12. fig. 34 (1838) °; Obs. Gen. Unio, ii. 
p. 39, t. 12. fig. 84°; Hanley, Cat. Rec. Bivalv. p. 193, t. 28. fig. 8 (male)’; Chenu, 
Illustr. Conch., Unio, t. 17. fig. 6°; Kiister, in Martini & Chemnitz, Syst. Conch.-Cab. 
ed. 2, Unio, p. 162, t. 46. fig. 57; Sowerby, in Reeve’s Conch. Icon. xvi., Unio, t. 38. 
fig. 171°; Fisch. & Crosse, Miss. Scient. Mex., Moll. u. p. 603 - 
? Unio veracruzensis, Lea, Proc. Acad. Phil. 1868, p. 150"; Obs. Gen. Unio, xii. p. 80, t. 52. 
fig. 133”. 
* See footnote, anted, p. 500. 
